Gaseous dischargefdevices having a free



Jan. 31, 1956 A. H. FAULKNER 2,733,374

GASEOUS DISCHARGE DEVICES HAVING A FREE AUXILIARY CONTROL ELECTRODE Filed Jan. 25. 1951 FIG. I

FIG. 3

I N V EN TOR. ALFRED H. FAULKNER flWfl/nd ATTORNEY Stat s.

This invention relates to gaseous discharge devices having at least three electrodes.

Gaseous discharge devices of the triode type have the auxiliary control electrode, such as the anode-starter,

positioned in the main discharge space, and hence the auxiliary control electrode acquires a potential dependent upon the space charge in the device. As a consequence thereof, the auxiliary control electrode draws current and produces a potential on the circuits connected thereto, and therefore the auxiliary control electrode cannot be treated as a free electrode.

Accordingly, an important object of the present invention is to provide a gaseous discharge device having the auxiliary control electrode free after ionization has transferred to the main gap, and the starting potential has been removed from the auxiliary control electrode.

Another object of the present invention is to provide a cold-cathode type gaseous discharge device having the starter-anode free after ionization has transferred to the main gap, and the starting potential has been removed from the starter-anode.

Other objects will appear upon further perusal of the detailed description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a front elevation view of a gaseous discharge device embodying the present invention.

Fig. 2 is a sectional view taken along the line 22 of Fig. 1.

Fig. 3 is a side elevation of a gaseous discharge device embodying the present invention.

As shown in the drawing, a gaseous discharge device 10, such as the cold-cathode type herein provided, comprises a conventional enclosing vessel or envelope having suitable ionizable gas therein. A cathode 12, in the preferred embodiment, is in t e form of a cylinder, and an anode 13, also in the preferred embodiment, is in the form of a rod-shaped wire directed along the axis of the cylindrical cathode 12. This form of construction enables a large cathode area to be enclosed in a small envelope.

Suitable means are provided for supporting the cathode 12, such as welding the cathode 12 to a pair of supporting wires 14 and 15, which extend through the press-end 16 of the envelope 11. It is intended that the supporting wires 14 and 15 be quite rigid so that they may be used to position the cathode 12 in the envelope 11 during assembly. After the press 16 has been formed, one of the supporting wires may be clipped off near the press-end, while the other supporting wire provides a cathode lead-in-connection. The supporting wires 14 and 15 extend slightly beyond the end of the cathode 12 at the seal-off end 17 of the envelope 11.

For accurately positioning the cathode 12 and the anode 13 relative to one another, a suitable disc such as mica disc 18 is provided having three aligned punched holes in it for inserting therein, the wire anode 13 and the supporting wires 14 and 15. The supporting wires 14 and 15 after being inserted in the mica disc 18 are 2,733,374 Baterited Jan. 31,1956

. crimped or bent to secure the discthereto. The anode 13' extends through the center hole in. the mica disc 18-, thereby accurately positioning the anode 13 and the cathodelZ. l v a According; to the inventiomian auxiliary control. electrode such. as starter anode 19, which is formed of a rod-shaped wire, extends through the press 16 and ter- (nitrates,lg et'ore. reaching a bent or transverse portion 20 'of, gthe cathode supporting wire 15.- The distance. between. th starter anode19 and theanode- 13 is greater thle d stancebetween the cathode. 12 and the anode Also, the starter-anode 19 to cathode 12. gap is locatedoutside or the main anod'e 13 to cathode 12 discharge space. This construction enables the starteranode 19 to be free after ionization has transferred to the main gap, and the starting potential has been removed from the starter-anode 19. Consequently, the starter-anode 19 being positioned outside of the main discharge space does not acquire a potential dependent upon the space charge in the main discharge space. eretofore, the potential acquired by the starter-anode interconnected so as to be interdependent, such as in a In such circuits the potential on the starter-anode of an ionized tube may greatly reduce the operating limits of another tube connected thereto by biasing it unfavorably.

In operation, suitable potential is initially impressed on the starter-anode 19 to initiate ionization between the cathode supporting Wire 15 and the starter-anode 19. With low values of starter-anode current the discharge is confined to the portion of cathode supporting wire 20 that is immediately adjacent to the starter-anode. With increasing values of starter-anode current the discharge spreads along the cathode wire 20 and eventually extends to the cathode cylinder 12. The value of starteranode current necessary to effect transition of the distransferred to the main gap the potential impressed on the starter-anode may be removed. The discharge is now confined within the cathode cylinder, leaving the starter-anode virtually free.

It is to be understood that modifications and variations may be effected without departing from the scope of the appended claims.

What is claimed is:

1. A cold cathode type gaseous discharge tube comprising an envelope enclosing a cathode, an anode, and

said cathode and extending through the envelope of said who, said cathode including a cylindrical shaped portion encompassing a space within itself including the electron gathering portion of said 2 A cold cathode type gaseous discharge tube comprising an envelope enclosing a cathode, an anode, and

a starter-anode, said cathode being in the form cylinder, a. pair of extending through said tube, said anode being in the form of a rod and longitudinally mounted withinand along the axis of said- -which is mounted within 'saidcathode cylinder forming a'imain discharge gap with inner surface of said cathode cylinder, said starter-anode being in the form of a rod cathode,-the portion of said anode of a rods supporting said cathode -and-- and extending through said tube and mounted independ- I ansaeu I other end of said cylindrical cathode, the flared portions of said-supporting--rods effective to confine the electrical field existing during discharge of said tube within said cylindrical cathode for confining the emitted electrons within said main discharge space and thereby preventing said emitted electrons from impinging upon the starterelectrode and creating a potential thereon.

References Cited in the file of this patent UNITED STATESrPATENTS r 1,875,151 Rentschler Aug. 30, 1932 2,250,264 Ingram July 22, 1941 2,415,816 Depew et a1 Feb. 18, 1947 2,560,347 Peck July 10, 1951 2,578,370 Peck Dec. 11, 1951 2,593,109 Craft, 3rd Apr. 15, 1952 

